Fifa has confirmed semi-automated, state-of-the-art technology will be used at the World Cup in Qatar to speed up the time taken to reach offside decisions.
In addition to a sensor in the middle of the ball, which sends data 500 times a second to determine the exact kick-point, 12 dedicated multi-tracking cameras that are "100% synchronised" will be mounted on the roof of each stadium to track the ball and 29 points on each player, sending data 50 times per second to calculate their exact position on the pitch.
Any player in an offside position will trigger an alert in the video assistant referee booth that can be relayed to the on-pitch referee.
The system was trialled at last year's Arab Cup and Club World Cup, where it was estimated to have reduced the time taken to make offside VAR decisions from 70 to 25 seconds.
"We are very positive. It is ready," said Fifa's head of refereeing Pierluigi Collina.